EVIDENCE OF MYOCARDIAL ISCHEMIC PRECONDITIONING AS SEEN ON ELECTROCARDIOGRAM AND IN ANGINAL PAIN RESPONSES OF PATIENTS UNDERGOING PERCUTANEOUS TRANSLUMINAL ANGIOPLASTY.
Contributors: University of California, San Francisco.
Published: 1996
Number of pages: 156
Subjects: Health Sciences, Medicine and Surgery.; Health Sciences, Nursing.
Description: Recent studies indicate that short, repetitive episodes of myocardial ischemia increase tolerance to subsequent ischemic episodes, a phenomenon known as preconditioning. To determine if this occurs in coronary arteries during elective percutaneous transluminal coronary angioplasty, ST segment deviations were measured on continuous 12-lead electrocardiograms in 33 subjects and anginal pain data in 30 subjects were recorded during 2-3 repetitive balloon inflations. The vessels undergoing angioplasty were the left anterior descending artery ($n=14$), the left circumflex artery ($n=11$), the right coronary artery ($n=8$). Inflation times ranged from 20-120 seconds (mean = 79 $\pm$ 24 (SD) seconds) for the first inflation followed by 3-5 minutes of reperfusion before the second inflation. The ST segment score, calculated as the sum of absolute values of ST segment deviation in all 12 leads, was measured at constant time intervals after onset of balloon inflation. When compared with the first balloon inflation, ST segment deviation decreased during the second inflation (mean = 11.8 $\pm$ 8.1 vs. 12.4 $\pm$ 7.5, $p<.05$) and subjective anginal pain decreased for 17 of 30 subjects (57%) with inflation 1 vs. 12 of 30 subjects or 40% with inflation 2, $p<.05$). Thirteen patients (43%) experienced silent ischemia. There was no relationship between the duration of first balloon inflation and the degree of reduction in ST score with subsequent inflation ($r=-.15$, NS). In conclusion, the decrease in magnitude of ST segment deviations and frequency of anginal pain provides clinical evidence of myocardial adaptation to ischemia. The physiologic mechanism of the adaptation has yet to be determined.
Notes: Source: Dissertation Abstracts International, Volume: 57-12, Section: B, page: 7443.

Thesis (PH.D.)--UNIVERSITY OF CALIFORNIA, SAN FRANCISCO, 1996.

School code: 0034.